Catechins are reported to be effective for suppressing an increase in the cholesterol level or inhibiting amylase activity (Patent Documents 1 and 2). In order to gain such physiological effects of catechins, an adult is required to drink four to five cups of tea a day. Thus there has been a strong demand for the development of a technology by which a high concentration of catechins is contained in a beverage so that a large amount of catechins can be consumed conveniently.    [Patent Document 1] JP-A-60-156614    [Patent Document 2] JP-A-3-133928